1. Field of the Invention
The present invention relates to a rotary falling machine for filling containers with liquids.
The machine in question is intended to be used in bottling plants of the type consisting of a rotating platform (or carousel) provided peripherally with a plurality of filling valve assemblies.
More particularly, the machine in question may be used optimally in the sector for the bottling of beverages such as wine, mineral water, etc.
2. Description of the Prior Art
According to the conventional technique, each filling valve assembly is provided with an obturator which regulates the supply of the liquid (for example wine) into a container (for example a bottle) arranged coaxially below the valve assembly.
The obturator is mounted inside a tubular duct designed to connect it to a storage tank from where the liquid descends by means of gravity into the containers. The duct has, mounted inside it, a pipe inside which the gas or air passes during some steps of the filling cycle.
The bottom part of this pipe has the function or regulating hydraulically the maximum level of the liquid inside the container which, when reached, causes hydraulic stoppage of the supply of liquid.
As is known, filling machines require frequent flushing operations in order to clean all the parts of the valve assemblies such that the bacterial level can be kept under control as far as possible.
These operations require circulation of the flushing fluid (consisting mainly of suitable aqueous solutions) in all the ducts where the liquid passes and where the air passes.
At present, the system most used for carrying out flushing involves the use of auxiliary containers (so-called "dummy bottles") which are mounted, during the flushing step, underneath each valve assembly, so as to open each obturator allowing the recirculation of the flushing liquid from the liquid duct to the a return pipe.
Recently, machines which are able to perform automatically insertion of the "dummy bottles" underneath the valve assemblies have become widespread. They avoid the need to perform long manual operations in order to prepare each valve assembly for the flushing operations and allow in particular the execution of the flushing cycles to be programmed automatically.
These latter automatic machines, although improving the performance compared to those requiring manual preparation, have some disadvantages.
The main defect lies in the fact that these machines of the known type, once the flushing cycle has been completed, discharge in a non-reusable manner onto the underlying plates (which carry the bottles) the flushing fluid present in each valve assembly.
This fact obviously results in loss of a considerable quantity of flushing fluid and in particular in the machine being soiled by the fluid itself.
It should be noted, therefore, that in this type of machine, whenever it is necessary to discharge the liquid being used (not only the flushing fluid, but also when the filling fluid is changed), the same problem is encountered, namely that of having to discharge onto tine machine itself that portion of liquid present in the valve assemblies which, being below the discharge level of the tank, cannot be emptied from below with opening of the obturators. This opening operation is in most cases performed manually and therefore requires that an operator be employed for a considerable amount of time. The flushing machines of the known type mentioned above are preceded, in the bottling process, by rinsing machines (with or without the insertion of inert gas aimed at cleaning the containers and reducing as far as possible the presence of oxygen inside them.
This is done because one of the main problems of the bottling process is to ensure preservation of the product, in particular to prevent oxidization as far as possible. In fact, as is known, the organoleptic and qualitative characteristics of some food products (such as wine) alter significantly, even if subject to a slight degree of oxidization.
Some rinsing machines used nowadays remove the air from the bottles by replacing it with inert gas (usually nitrogen or carbon dioxide), after which the bottles continue on conveyors as far as filling machines such as those in question. During this travel movement, part of the inert gas present in the (open) bottles is dispersed and replaced with air. Moreover, once filling of the bottles has been completed, extraction of the liquid supply duct creates a slight vacuum with consequent drawing-in of outside air into the bottle.
Another type of filling machine of the known type (called isobaric) solves the problem of oxidization by removal, during a first step, of all the air from the bottle (creating a vacuum of the order of 80-90% inside it) and injection of inert gas under pressure during a next step, prior to filling. This type of machine, however, is very costly, has a low productivity and requires that the bottles be subjected to pressures which may risk breaking them.
It should be noted, moreover, that the filling machines in question operate with the storage tank under a slight vacuum generated by special pumps. These pumps therefore regulate, with their action, the value of the pressure present inside the storage container. This regulating action is somewhat problematic in the case of machines provided with an air return pipe which results in the connection with the storage tank being kept open irrespective as to whether containers are present or not underneath the valve assemblies.
In fact, a continuous flow of air is able to enter through the pipes of the valve assemblies arranged in front of the machine (where, that is, no bottles are present).
This flow, on the one hand, does not allow easy adjustment of the pressure inside the tank and, on the other hand, continuously draws in outside air (which is therefore rich in oxygen) inside the storage tank, thus exposing the filling liquid to a high risk of oxidization.
Furthermore, the filling machines provided with air return pipes which are closed at the bottom when there are no containers (such as those provided with liquid supply ducts lined with external sheaths capable of descending and closing off the side holes through which the air passes when there are no containers are characterized by poor productivity. This is due to the fact that, when the obturator is opened, these machines must wait for a fairly long period of time in order to allow compensation between the pressure of the gaseous mixture present in the storage tank and the gaseous mixture present in the container to be filled.
The essential object of the present invention is therefore to overcome the drawbacks associated with the systems of the known type by providing a rotary filling machine which allows automatic flushing of all its parts to be performed without requiring the non-reusable discharging of the flushing liquid remaining in each valve assembly.
A further object of the present invention is that of providing a machine which is constructionally sample and operationally entirely reliable and allows an inert gas to be inserted inside the containers before, during and at the end of the filling step.
Another object of the machine in question is to provide rapid compensation between the pressure of the gas mixture present in the storage tank and that of the gas mixture present inside the container, while maintaining a high level of productivity and allowing easy regulation of the pressure of the gaseous mixture present in the storage tank.